No specific reason, just that it seems to speak from and to most of our life's experiences....both sad and happy. You know, at some point in life some one...a colleague at work, a sibling, a parent, a neighbor.......yes, some one either left, or will leave, and what you are left with, is the reminder of that empty chair, physically or even symbolically.
The point is, life twists us in more ways as can only be reminded as by the specter of an empty chair....It stirs in my large volumes of emotion, and freewriting them is allowing me to break free!!!